This disclosure relates to an electrical junction box to be mounted on a motor vehicle, and more particularly relates to an electrical junction box which contains printed circuit boards, can reduce a count of components to be contained, can simplify a construction, and can accomplish sliming and downsizing purposes.
An electrical junction box to be mounted on a motor vehicle is required for accommodating a plurality of printed circuit boards, on which electrical parts and electronic parts are mounted, together with conventional common laminated unit including bus bars and insulation plates, in association with a rapid increase of electrical parts to be mounted on the motor vehicle. Because parts to be mounted in the electrical junction box has increased, a construction of the electrical junction box has tended to be complicated and upsized
For example, an electrical junction box disclosed in Japanese Patent No. 3888368, as shown in FIG. 6 of the present application, has a casing assembly including an upper casing 1, an intermediate casing 2, and a lower casing 3. A laminated unit 4 including bus bars and insulation plates is contained in an upper part of a space between the upper casing 1 and the intermediate casing 2, while a first printed circuit board 5 is contained in the lower part of the space. A multi functional interexchange unit 6 is disposed in a space between the intermediate casing 2 and the lower casing 3 and a relay unit 7 is disposed below the interexchange unit 6 in the space. The multi functional interexchange unit 6 is provided with a second printed circuit board 8 while the relay unit 7 is provided with a third printed circuit board 9.
The first, second, and third printed circuit boards 5, 8, and 9 are connected to one another through interexchange connectors provided in the multi functional interexchange unit 6.
In the electrical junction box constructed above, as schematically shown in FIG. 7, the intermediate casing 2 is disposed between the upper casing 1 and the lower casing 3 to form a casing assembly comprising three components. The first printed circuit board 5 is supported by the lowermost insulation plate of the laminated unit 4, the second printed circuit board 8 is supported by the multi functional interexchange unit 6, and the third printed circuit board 9 is supported by the relay unit 7. Since the printed circuit boards are supported by the different members, the number of components increases.
Thus, the increased number of components and complicated construction will upsize the electrical junction box and incur a very high cost.